Medical data display systems such as patient monitoring systems play an important role in assessing and monitoring the well-being of patients receiving care (whether during a procedure or as part of recovery). Various vital signs such as ECG, basic arrhythmia, respiration, pulse rate, temperature, noninvasive blood pressure and SpO2 can be simultaneously displayed. Some of these vital signs are displayed as waveforms that have values which vary over time. In some cases, a caregiver may need to pay special attention to one of the waveforms.